[BUG]: plot_spawning_biomass grabs additional values

[Schiano-NOAA]

When values exist where there is a prefix to spawning_biomass in plot_spawning_biomass then both are plotted.

Need to either add ^ to the beginning of the grepl to fix this, but now this needs to be tested with all of the other examples

This part can be edited:

stockplotr/R/plot_spawning_biomass.R

Lines 118 to 128 in f81c7b5

	prepared_data <- filter_data(
	dat = dat,
	label_name = "spawning_biomass$",
	geom = geom,
	era = era,
	group = group,
	facet = facet,
	module = module,
	scale_amount = scale_amount,
	interactive = interactive
	)

I found the issue from a FIMS output after running:

knitr::purl(
  input = 'https://raw.githubusercontent.com/NOAA-FIMS/FIMS/refs/heads/main/vignettes/fims-demo.Rmd',
  output = 'fims_demo.R',
  documentation = 0
)
source('fims_demo.R')
sb <- dplyr::filter(output, grepl("spawning_biomass", label))
unique(sb$label) # results in >1 label name